The success of return to sport after ulnar collateral ligament injury in baseball: a systematic review and meta-analysis.

BACKGROUND: Ulnar collateral ligament injury (UCLI) has significantly increased in overhead sports during the past 2 decades. Differences in return to sport (RTS) and RTS at previous level (RTSP) after UCLI have not been differentiated.

METHODS: A computer-assisted literature search of PubMed, CINAHL, Embase, and SportDiscus databases using keywords related to RTS for UCLI was implemented. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were used for study methodology. Quality assessment was conducted using a modified Downs and Black scale.

RESULTS: A total of 22 retrospective, level 3b or 4, studies (n = 2289) qualified for analysis. Overall RTS proportion was 90% (95% confidence interval [CI], 86%-94%) and overall RTSP proportion was 79% (95% CI, 75%-84%), both with significant heterogeneity (P < .001, I2  = 74%-84%). RTS and RTSP proportions were 89% (95% CI, 83%-94%) and 78% (95% CI, 72%-83%) for Major League Baseball players, 91% (95% CI, 77%-99%) and 67% (95% CI, 52%-81%) for Minor League Baseball players, 95% (95% CI, 75%-100%) and 92% (95% CI, 82%-98%) for collegiate players, and 93% (95% CI, 81%-100%) and 83% (95% CI, 77%-89%) for high school players, respectively. Increased earned run average, walks, and hits per inning pitched, decreased innings pitched, and decreased fastball velocity were found after UCLI.

CONCLUSION: Low-level, high-bias evidence demonstrates overall RTS proportion is higher than RTSP, regardless of treatment type for UCLI. Although RTS proportions remained consistent across various levels of play, RTSP proportions were lower in professional players, particularly Minor League Baseball compared with collegiate and high school players. Pitching performance significantly decreased postoperatively in most studies.